Various discussions have hitherto been made as to a dephosphorizing process in sewerages, rivers, or the like, and pilot experiments have been conducted in various regions of the country. For example, a contact dephosphorizing method is known, wherein a phosphorus-containing aqueous solution is controlled under appropriate conditions, and contacted with a compound of the same species and same system consisting of calcium phosphate, thereby forming and crystallizing calcium phosphate (hydroxy apatite) on the above compound.
According to the above contact dephosphorizing method, the concentration of the phosphorus component contained in water can be lowered effectively. However, pH of the phosphorus-containing water should be adjusted by a decarboxylating process or addition of lime in order to control such crystallizing reaction, and such control should be done all the time, which causes a drawback of complicating the process. Therefore, there is demanded a development of a method capable of effectively removing phosphorus component with economical superiority, easiness, and convenience, and of a dephosphorizing material usable in such a method.